TESTING OF AN EMERGENCY LIGHTING SYSTEM IN A DOMESTIC PREMISES , IS TO ENSURE THAT IN THE CASE OF POWER FAILURE DUE TO A FIRE OR OTHER CAUSE PEOPLE CAN EVACUATE THE BUILDING IN A SAFE MANNER WITH OUT CAUSING INJURY TO THEMSELVES . THIS TEST IS REQUIRED EVERY SIX MONTHS . THE CERTIFICATE IS ISSUED ON SITE AFTER THE TEST IS COMPLETED . AVAILABLE IN EVERY MAINLAND UNITED KINGDOM POSTCODE